News NASA's Actual Plan to Deflect an Asteroid

Andy44

owner: Oil Creek Astronautix
Addon Developer
Joined
Nov 22, 2007
Messages
7,620
Reaction score
6
Points
113
Location
In the Mid-Atlantic states
http://news.yahoo.com/nasas-actual-...ng-asteroid-234624320--abc-news-politics.html

From the 2007 NASA report to Congress:
In the impulsive category, the use of a nuclear device was found to be the most effective means to deflect a PHO. Because of the large amount of energy delivered, nuclear devices would require the least amount of detailed information about the threatening object, reducing the need for detailed characterization. While detonation of a nuclear device on or below the surface of a threatening object was found to be 10-100 times more efficient than detonating a nuclear device above the surface, the standoff detonation would be less likely to fragment the target. A nuclear standoff mission could be designed knowing only the orbit and approximate mass of the threat, and missions could be carried out incrementally to reach the required amount of deflection. Additional information about the object's mass and physical properties would perhaps increase the effectiveness, but likely would not be required to accomplish the goal. It should be noted that because of restrictions found in Article IV of the "Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space," including the Moon and Other Celestial Bodies, use of a nuclear device would likely require prior international coordination. The study team also examined conventional explosives, but found they were ineffective against most threats.

Links to NASA report and charts on the page.
 

Suzy

Member
Joined
May 27, 2008
Messages
390
Reaction score
0
Points
16
Location
Melbourne
Website
suzymchale.com
Can ICBMs (if that's what would be used) be guided into orbit beyond Earth? Or would a missile have to be designed specifically?
 

boogabooga

Bug Crusher
Joined
Apr 16, 2011
Messages
2,999
Reaction score
0
Points
0
Can ICBMs (if that's what would be used) be guided into orbit beyond Earth? Or would a missile have to be designed specifically?

There is no reason for an off-the-shelf ICBM to have the delta-V for escape velocity.
 

Andy44

owner: Oil Creek Astronautix
Addon Developer
Joined
Nov 22, 2007
Messages
7,620
Reaction score
6
Points
113
Location
In the Mid-Atlantic states
Can ICBMs (if that's what would be used) be guided into orbit beyond Earth? Or would a missile have to be designed specifically?

There is no reason for an off-the-shelf ICBM to have the delta-V for escape velocity.

The original Atlas was an off-the-shelf ICBM that was capable of putting satellites into orbit, including manned Mercury capsules, and with an Agena or Centaur was quite useful as a general purpose space launcher.

Current solid-fuel ICBMs are probably less versatile, since the solid upper stages have no re-start capability. You also need to write some new software, etc. But I'm sure something could be worked out. Solid fuel missiles are much easier to handle and store long-term; it's like keeping a loaded shotgun behind the kitchen door, you load it and don't have to fuss with it much, until you see the asteroid coming and you can pull it out and shoot at the last minute. Liquid-fuel rockets are more versatile once they're flying, but they are tougher to maintain on the ground.

You also have to honor diplomacy to avoid misunderstandings. I imagine you'd want to have a launch complex set aside strictly for asteroid deflection purposes, which you would allow foreign inspection of for treaty verification purposes, and of course if you needed to launch you'd tell everyone in advance exactly what you were doing.
 

T.Neo

SA 2010 Soccermaniac
Addon Developer
Joined
Jun 22, 2008
Messages
6,368
Reaction score
0
Points
0
The original Atlas was an off-the-shelf ICBM that was capable of putting satellites into orbit, including manned Mercury capsules, and with an Agena or Centaur was quite useful as a general purpose space launcher.

It's a matter of payload; an ICBM may be able place an object of a certain mass in orbit, but lob its warhead(s) only several thousand kilometres away. In any case, getting beyond LEO would require a capability that ICBMs simply don't have. Perhaps a modern ICBM could be developed into a system that could launch payloads on escape trajectories, but by that point you'd basically have a different vehicle, and it'd be fairly kludge-y anyway.

At least in terms of getting the required amount of mass to the asteroid, modern small or medium launchers are probably a better option.
 

jedidia

shoemaker without legs
Addon Developer
Joined
Mar 19, 2008
Messages
10,388
Reaction score
1,634
Points
203
Location
between the planets
Wouldn't it be simpler to just put a warhead on top of a more capable lancher? Noone said you had to fire an ICBM, just because that's what nukes are usually strapped to...

Anyways, NASA's official policy concerning asteroids: Shoot first, ask questions later! :p
 

MattBaker

New member
Joined
Jul 9, 2011
Messages
2,750
Reaction score
0
Points
0
There were protests over 36 kilograms of Plutonium inside Cassini which would do an Earth flyby and could potentially reenter if there's a failure.

I wonder what people will then think about launching a nuclear device atop a launcher.

And the W88 warhead has a yield of 475 kt while weighing around 360 kilograms, so I think you could do the job with quite a small launcher like a Delta II.
 

BruceJohnJennerLawso

Dread Lord of the Idiots
Addon Developer
Joined
Apr 14, 2012
Messages
2,585
Reaction score
0
Points
36
I recall that since the 70s or so, most nuclear weapons are designed target-specific. I doubt there's been any work done on a specific asteroid-buster version, but what would it look like if there was one? (ie how do you optimize a nuke for this job?)
 

Michkov

Member
Joined
Apr 4, 2008
Messages
128
Reaction score
16
Points
18
Project Orions propulsion nukes would be a good starting point. IIRC they were build so that the blast was directed against the spacecraft.
 

boogabooga

Bug Crusher
Joined
Apr 16, 2011
Messages
2,999
Reaction score
0
Points
0
There were protests over 36 kilograms of Plutonium inside Cassini which would do an Earth flyby and could potentially reenter if there's a failure.

I wonder what people will then think about launching a nuclear device atop a launcher.

Totally different situation when a society-ending asteroid is on its way. If they would prefer to die...

I would worry more about radicals who would prefer to see the asteroid hit based on religious belief.


The original Atlas was an off-the-shelf ICBM that was capable of putting satellites into orbit, including manned Mercury capsules, and with an Agena or Centaur was quite useful as a general purpose space launcher.

Adding an upper stage = not off-the-shelf.
LEO capability != escape capability (with excess C3)

Basically to answer the question- no, ICBMs are not suitable; something else will have to be designed, probably using existing dedicated space launchers.
 
Last edited:

Andy44

owner: Oil Creek Astronautix
Addon Developer
Joined
Nov 22, 2007
Messages
7,620
Reaction score
6
Points
113
Location
In the Mid-Atlantic states
Actually, you want something like an ICBM. Particularly you want solid fuel stages. Remember that this is something that may never be needed, but if it is needed it may be needed very very badly and quickly.

So you want something that's not too costly to maintain, and very reliable after being stored for long periods of time. You also want it to be able to react quickly, since the guy in charge of pushing the "button" is likely to wring his hands until the last minute because he will be a politician worried about public opinion and foreign reaction and will want to be sure he really needs to do this before committing to it.

Remember, though, that the Earth has gone without protection for thousands of years since the last mass extinction, so maintaining any kind of asteroid defense will be very difficult to do politically in the long run.
 

BruceJohnJennerLawso

Dread Lord of the Idiots
Addon Developer
Joined
Apr 14, 2012
Messages
2,585
Reaction score
0
Points
36
Actually, you want something like an ICBM. Particularly you want solid fuel stages. Remember that this is something that may never be needed, but if it is needed it may be needed very very badly and quickly.

So you want something that's not too costly to maintain, and very reliable after being stored for long periods of time. You also want it to be able to react quickly, since the guy in charge of pushing the "button" is likely to wring his hands until the last minute because he will be a politician worried about public opinion and foreign reaction and will want to be sure he really needs to do this before committing to it.

Remember, though, that the Earth has gone without protection for thousands of years since the last mass extinction, so maintaining any kind of asteroid defense will be very difficult to do politically in the long run.

Storable Hypergolics could work too, couldn't they? I would suspect that you would want at least some sort of liquid fueled upper stage with the warhead for course corrections. The whole point of using a nuke on an asteroid is to be precise, so it would probably need to rendezvous with it first as well.
 

Andy44

owner: Oil Creek Astronautix
Addon Developer
Joined
Nov 22, 2007
Messages
7,620
Reaction score
6
Points
113
Location
In the Mid-Atlantic states
Yeah, hypergolics are storable, but you still have to service the tanks and engines periodically, which means handling very hazardous chemicals and spending more money. That's one reason the USAF went with the solid fuel Minuteman.

As far as course corrections, the Minuteman series does it somehow, maybe the warhead busses use hypergolics? In this case you would only need to service the upper stage, which is better than having to service the entire booster.

It is mathematically possible to do the entire asteroid intercept using only solid fuel, as long as you factor in a fixed impulse for each thruster firing, and the fact that each firing uses up a thruster, so you only have a limited number of thrusters to use up.
 
Last edited:

Loru

Retired Staff Member
Retired Staff
Addon Developer
Donator
Joined
Sep 30, 2008
Messages
3,731
Reaction score
6
Points
36
Location
Warsaw
I think the best "off the shelf" option here is to use [ame="http://en.wikipedia.org/wiki/Minotaur_V"]Minotaur V[/ame].

All stages are solid and fith stage (Star-37FMV) has 3 axis stablilsation. 437kg to TLI makes it suitable for pretty solid nuke (for example 475kT W88 warhead weighting 360kg).
 

Andy44

owner: Oil Creek Astronautix
Addon Developer
Joined
Nov 22, 2007
Messages
7,620
Reaction score
6
Points
113
Location
In the Mid-Atlantic states
Ah, yes, the Minotaur, which is made partly of recycled ICBM parts. That sounds about right. You'd still need to modify one or two along with a launch facility to have them at the ready, but they are attractive.
 

T.Neo

SA 2010 Soccermaniac
Addon Developer
Joined
Jun 22, 2008
Messages
6,368
Reaction score
0
Points
0
Actually, you want something like an ICBM. Particularly you want solid fuel stages. Remember that this is something that may never be needed, but if it is needed it may be needed very very badly and quickly.

"Very very badly" and " very very quickly" may hold true, but they're defined differently here to in the situation of a nuclear war, though. Firstly, the fact that a capable enemy will attempt a counterforce strike against one's nuclear assets is one of the forces driving the design of ICBMs and their launch complexes. While the consequences of a bolide impact are pretty bad- potentially considerably worse than those of a limited nuclear exchange- bolides do not specifically target deflection spacecraft launch sites, nor does the ability of a launch site to withstand a specific degree of bombardment have much impact on one's ability to successfully deflect a bolide.

Secondly, bolide impacts are unique among disasters in their predictability- they can, in theory, be detected decades or perhaps even centuries in advance. Of course, a bolide could be detected only months or weeks in advance- the likelihood of such late detection being inversely proportional to how formidable one's observational capabilities are- but the earlier a bolide can be deflected, the better. Beyond a certain point, deflection becomes impossible, even with very powerful devices.

By comparison, the situation leading up to war is difficult to predict and can change considerably in a matter of weeks or days. An actual nuclear conflict would take place on the order of minutes; several tens of minutes for ICBMs, and even shorter for submarine-based or theatre missiles. Ideally, an ICBM must be constantly ready to launch, and launch as instantly as possible. If the threat of a bolide impact is playing out at the speed of nuclear war, not only has any attempt to deflect the object become futile long ago, but the spaceguard program in question is criminally negligent.

Launch vehicles are constantly being produced, shipped and made ready for launch. In a realistic scenario, it probably wouldn't be too much trouble to appropriate one of these boosters for a deflection mission. The logistics certainly wouldn't pose a problem for timescales of several years, and probably not for timescales of several months. If it were especially necessary, one might be able to keep a launcher stacked or out on the pad until needed. The time needed for fueling a vehicle for launch isn't much at all, and even the time needed for stacking and rollout probably wouldn't pose a problem in a realistic scenario.

There were protests over 36 kilograms of Plutonium inside Cassini which would do an Earth flyby and could potentially reenter if there's a failure.

In a situation where a bolide is predicted to impact Earth with considerable certainty, the possibility of such radiological contamination is acceptable. The probability of a contamination-causing failure of the Cassini launch was calculated at perhaps a one in a few hundred (link). Presumably the probability of contamination would be similar here, though the material within a nuclear device is also less radioactive than that within an RTG.

Even a small bolide- a few hundred meters across- could potentially kill over ten million people and do a great deal of damage in terms of infrastructure. Even the worst-case outcome of contamination from a launch failure likely pales in comparison to such effects.

437kg to TLI makes it suitable for pretty solid nuke (for example 475kT W88 warhead weighting 360kg).

You need to carry more than just the nuke though- you also need to carry the spacecraft bus that will carry the thrusters and propellant to maneuver the device into position, avionics, communications equipment, power supply, etc. Some kind of equipment to determine distance to the asteroid and other conditions will probably be required as well.
 
Top